Disposal of inorganic chemical wastes

ABSTRACT

Recovery and disposing of waste materials containing inorganic chemicals  not be effected by incineration to meet environmental regulations as is the situation with waste organic materials. As long as the inorganic toxic materials are in some soluble form, they can pollute the environment, and, also, end up in the water supplies. Two different disposal methods are disclosed wherein one method is effective for removing the insoluble inorganic salts by converting them into mesylates by reaction with methanesulfonic acid or with methanedisulfonic acid. Most mesylate salts are highly soluble in aqueous and certain organic systems. As an illustration, 1.0 part of silver mesylate or 2.0 parts of stannous mesylate or lead(II) mesylate will dissolve in 1.0 part of water at room temperature. This unique solubilizing property offers the ability of leaching such toxic metal contaminants as lead, cadmium, etc. from sewage sludge. The metal salts can thus be recovered and recycled. The other method relates to preparing the waste material for a safe burial without concern of contaminating the environment. This method is achieved by the following procedure: any acidic waste inorganic material is neutralized using a slurry of slaked lime. The neutralized material is then combined with the remainder of the waste material. The waste material is transferred to a polyethylene bag which is used to line the inside of a container. The waste material is then placed in the polyethylene bag, and mixed with enough sand and portland cement to produce a mixture that will harden overnight. The resulting block of concrete, contained within the polyethylene bag, can be buried safely without concern of contaminating the environment.

DEDICATORY CLAUSE

The invention described herein may be manufactured, used, and licensedby or for the Government for governmental purposes without the paymentto me of any royalties thereon.

BACKGROUND OF INVENTION

The disposal of waste materials containing inorganic chemicals cannot beeffected by incineration as is the situation with typical organic wastematerials. Typical organic waste material when burned yield gaseousproducts which can be safely disposed of in accordance withenvironmental regulations. To the contrary, inorganic materials havingtoxic components when burned can still yield toxic products which are insome soluble form which make them conducive to polluting theenvironment, and also ending up in the water supplies.

Thus, there is an immediate need for an effective method of removing theinsoluble inorganic salts from waste materials such as sewage sludge.

Therefore, an object of this invention is to provide a method forremoving insoluble inorganic salts from waste materials by convertingthem to a soluble form which can be recovered and recycled or which canbe safely disposed of without contaminating the environment.

A further object of this invention is to provide a method which convertsinsoluble inorganic salts into highly soluble acidic products which aresoluble in aqueous and selected organic systems.

Still a further object of this invention is to provide a method whichconverts waste portions of inorganic material to a neutralized formwhich is subsequently converted to a solid form which can be buriedsafely without concern of contaminating the environment.

SUMMARY OF THE INVENTION

Insoluble inorganic salts of waste materials are effectively removedfrom the waste materials by reacting, while agitating the wastematerials with methanesulfonic acid or methanedisulfonic acid to convertthem into mesylates. The mesylate salts are highly soluble in aqueousand selected organic systems.

The unique solubilizing property of the mesylates offers the ability ofextracting such toxic metal contaminants as lead, cadmium, etc. fromsewage sludge. The metal salts can thus be removed and recycled.

Another or alternate disposal method for waste inorganic material isachieved by the procedure which includes neutralizing any acidicinorganic waste material with a slurry of slaked lime. The neutralizedmaterial is then combined with the remainder of the waste material. Thewaste material is transferred to a polyethylene bag which is used toline the inside of a container. A mixture of enough sand and Portlandcement is added and mixed to produce a mixture that hardens overnight.The resulting block of concrete, contained within the polyethylene bag,is buried safely without concern of contaminating the environment.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Inorganic salts contained in waste material such as sewage sludge areeffectively removed or disposed of by two different methods.

Method 1 is preferred where the toxic metal contaminants such as lead,cadmium, etc. are desired to be removed, recovered and recycled. Method2 is preferred where the toxic metals are other inorganic salt materialsare not desired to be recovered, but are desired to be safely buriedwithout concern of contaminating the environment.

Methanesulfonic acid (CH₃ SO₂ OH) and methanedisulfonic acid CH₂ (SO₂OH)₂ are effective in removing the insoluble inorganic salts byconverting them into mesylates. The mesylates salts which contain thetoxic metal components of the waste materials are highly soluble inaqueous and certain organic systems.

EXAMPLE I

Sludge or the waste material in a slurry form is treated while beingagitated with a stoichiometric excess of a methanesulfonic acid to yieldmetal mesylates which are highly soluble in water. As an illustration,1.0 part of silver mesylate or 2.0 parts of stannous mesylate orlead(II) mesylate will dissolve in 1.0 part of water at roomtemperature. Other insoluble inorganic salts containing toxic metalcontaminants as lead, cadmium, zinc, beryllium, chromium, nickel,vanadium, thallium, and etc., are extracted from sewage sludge. Themetals of the salts can be recovered and recycled.

EXAMPLE II

Acidic inorganic materials contained in waste are disposed of by thefollowing procedure: any waste acidic inorganic material is neutralizedusing a slurry of slaked lime. The neutralized material is then combinedwith the remainder of the waste material. The waste material istransferred to a polyethylene bag which is used to line the inside of acontainer. The waste material is then placed in the polyethylene bag,and mixed with enough sand and Portland cement to produce a mixture thatwill harden overnight. The resulting block of concrete, contained withinthe polyethylene bag, can be buried safely without concern ofcontaminating the environment.

I claim:
 1. A method of disposal of waste inorganic chemical materialcontaining insoluble inorganic salts of toxic metals, said methodcomprising:(i) treating said inorganic chemical waste material in theform of a slurry while being agitated with an excess of a stoichiometricamount of a compound selected from the compounds consisting ofmethanesulfonic acid and methanedisulfonic acid to convert saidinsoluble inorganic salts of toxic metals into metal mesylates; (ii)solublizing said metal mesylates in an aqueous or a polar organicsolvent system; and, (iii) recovering said metal mesylates which containtoxic metals leached from said inorganic chemical waste materials. 2.The method of claim 1 wherein said inorganic chemical waste material isin the form of sewage sludge and wherein said insoluble inorganic saltscontain the toxic metals comprising lead, cadmium, zinc, beryllium,chromium, nickel, vanadium, and thallium.
 3. A method of disposal ofacidic organic chemical waste material which comprises;(i) neutralizingwhile agitating a portion of said acidic inorganic chemical wastematerial using a slurry of slaked lime; (ii) combining a remainingportion of said acidic inorganic chemical waste material in sufficientquantity to retain neutrality of the combined said portions and saidslurry of slaked lime; (iii) transferring said neutralized acidicinorganic chemical waste material to a polyethylene bag which is used toline the inside of a container; and (iv) combining a sufficient amountof sand and portland cement with said neutralized acidic inorganicchemical waste material to produce a mixture that will harden overnightto form a block of concrete, contained within said polyethylene bag andin a suitable form for being buried safely without concern ofcontaminating the environment.